Good price on a second hand deal. This lens is three years old, but works perfectly. The wide end is incredible, despite the soft edges. The price included 82mm polarizer, which comes handy in every second moment.

I haven't used the manual focus ring too much. But I guess that switching the lens to manual doesn't do the trick, you have to adjust your camera body too. And on top of that, you have to pull the focus ring towards you to unlock the AF mode. This makes a funny popping noise

For the second hand price, excellent lens. But I wouldn't have bought it for it's list price (which here in Finland is close to 500 euros).

If you like the few extra mm this lens offers over the Tokina 19-35mm (or some other 3rd party small budget wideangle lens), Sigma is your choice if you can get it for under 300 $/euros.